makes ezic:local_to_utc errors into values; updates tests accordingly

Like in d98eed, errors are now returned as values rather than crashing
processes. This is a short-term solution for consistency, and can be
refactored to a saner model later.

src/ezic.erl

@@ -27,13 +27,8 @@ utc_to_local(UTCDatetime, TzName) ->
 %% returns utc time for corresponding time in given timezone utc
 local_to_utc(LocalDatetime, TzName) ->
     NormalDatetime= ezic_date:normalize(LocalDatetime, w),
-    #flatzone{offset=Offset, dstoffset=DSTOffset}= ezic_db:flatzone(NormalDatetime, TzName),
+    local_to_utc_handleFlatzone(LocalDatetime, ezic_db:flatzone(NormalDatetime, TzName)).
     
-    ezic_date:add_offset(
-      ezic_date:add_offset(
-	LocalDatetime
-	, Offset, {0,0,0})
-      , DSTOffset, {0,0,0}).
 
 
 
@@ -49,3 +44,14 @@ utc_to_local_handleFlatzone(UTCDatetime, #flatzone{offset=Offset, dstoffset=DSTO
     	UTCDatetime
     	, Offset)
       , DSTOffset).
+
+
+local_to_utc_handleFlatzone(_, X={error, _}) ->
+    X;
+local_to_utc_handleFlatzone(LocalDatetime, #flatzone{offset=Offset, dstoffset=DSTOffset}) ->
+    ezic_date:add_offset(
+      ezic_date:add_offset(
+    	LocalDatetime
+    	, Offset, {0,0,0})
+      , DSTOffset, {0,0,0}).
+